This application relates to a device and method for unfreezing the brake lines of tractor trailers when they become frozen.
An air brake schematic for a tractor trailer is shown in FIG. 1. A typical air brake system includes an air compressor 1 with a governor which directs compressed air to compressed air reservoir tank 5. The system can include an air drier 3 to remove moisture from the air, and dried compressed air can then be stored in reservoir tanks 8 and 10. At the rear of the trailer, the brake system includes brake valves 14 and 15, which are typically diaphragm valves. Valve 14 is the service brake valve, and valve 15 is a parking brake valve. The valves are connected to slack adjusters (not shown) which are connected to the brakes (i.e., brake linings and drums or rotors). The compressed air reservoirs 5, 8, and 10 are connected to the brake valves 14, 15 by emergency air lines 21 and control air lines 22. The compressed air reservoirs are in the tractor. Thus, the air lines each comprise a first part associated with the tractor and a second part associated with the trailer. These two parts are connected by means of connectors 20, such as glad hand-type connectors. A foot pedal 31 is located in the tractor to be pressed by the operator. Operation of the foot pedal 31 operates valving which releases air from the compressed air tanks, and delivers compressed air to the brake valves 14 and 15 over the control lines 22 to activate the trailer brakes.
Prolonged exposure to cold temperatures can cause moisture in the brake air lines and brake valves to freeze, thus freezing the air lines and brake valves. If brake air lines and valves do freeze, the trailer brakes become inoperable, thus creating potentially serious safety issues. For example, frozen brake air lines and valves can cause a tractor-trailer to jack-knife.
Releasing of the brakes (i.e., unfreezing of the brake lines and valves) requires that the operator exit the tractor, and detach the service hose extending from the tractor from the connector to the air line at the trailer. The connection of the service hose to the trailer air line is often done by means of a glad hand-type connector. A deicing agent, such as an air brake anti-freeze or an air brake evaporating alcohol, is poured into the service hose connector and the service hose is reconnected to the trailer via the mating connectors. The opening in the service hose connector is small, typically about 0.5″ (˜1.27 cm) in diameter. Hence, it is difficult to pour sufficient amounts of deicing agent into the service hose connector, and the operator will often spill at least some of the deicing agent.
The operator then returns to the tractor, and activates the service valve to apply air pressure to the brake valves at the back of the trailer. This will distribute the alcohol throughout the brake system. Then, the operator needs to go to the rear of the truck, climb under the truck, and, using a torch, heat the brake valves. The operator needs to be careful when heating the valves so as not to melt or otherwise damage the bushings and washers in the valve. Should that occur, the brake valves will need to be replaced, which will increase the operator's downtime and service charges. Once the valves are heated, the operator taps the slack adjusters with a hammer. If a sufficient amount of alcohol was not placed into the air system, the brakes may not release, and the procedure will need to be repeated.
As can be appreciated, this procedure is performed in the cold (i.e., when the temperatures are below freezing). Further, the operator must perform the procedure on the side of the road or highway. This exposes the operator to the hazards of performing procedures on the shoulder of a road or highway. If the operator can successfully release the frozen brakes, the operator can be operating again within a relatively short period of time (30 minutes or so). However, as noted above, the opening to the service line in the connector is small, and it is difficult to pour a sufficient amount of deicing agent into the service hose, at least without spilling the deicing agent. Thus, if the described procedure does not release the brakes, the operator will have to repeat the procedure. If a repeat of the procedure still does not release the brakes, the operator may need to call for repair services. As is known, a service call can dramatically increase the operator's downtime. This will impact the estimated delivery time for the product carried in the trailer. Additionally, service calls are typically expensive.
It would be desirable to provide a device which will more easily and reliably release frozen brake of a tractor trailer.